Hydrogen storage and release using a solid-state material e.g., sodium borohydride (NaBH₄) may fulfill the requirements for the ‘Hydrogen Economy’. This study reported ZnO-based materials for hydrogen release via the hydrolysis of NaBH₄. Two different metal oxides e.g. CeO₂ and TiO₂ with different weight loading (5 wt.% and 10 wt.%) were used during the synthesis via a simple combustion method. The synthesis procedure offered nanocomposites consisting of ZnO-xTiO₂, and ZnO-xCeO₂ (x = 5 wt.% or 10 wt.%). Diffraction techniques (X-ray (XRD) and electron diffraction (ED)) confirm the phase purity of the material. Diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy characterized the optical properties of the materials. The materials displayed a hydrogen generation rate (HGR) of 3000 mL·min⁻¹·g_cat⁻¹. Thermodynamic analysis revealed that ZnO, ZnO-10TiO₂, and ZnO-10CeO₂ catalysts have activation energies of 59.8, 36.8, and 27.5 kJ·mol⁻¹, respectively.

One-pot co-precipitation of target molecules e.g. organic dyes and the synthesis of a crystal containing microporous–mesoporous regimes of zeolitic imidazolate frameworks-8 (ZIF-8) are reported. The synthesis method can be used for cationic (rhodamine B (RhB), methylene blue (MB)), and anionic (methyl blue (MeB)) dyes. The crystal growth of the ZIF-8 crystals takes place via an intermediate phase of zinc hydroxyl nitrate (Zn₅(OH)₈(NO₃)₂) nanosheets that enabled the adsorption of the target molecules i.e., RhB, MB, and MeB into their layers. The dye molecules play a role during crystal formation. The successful encapsulation of the dye molecules was proved via diffuse reflectance spectroscopy (DRS) and electrochemical measurements e.g., cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The materials were investigated for carbon dioxide (CO₂) adsorption and adenosine triphosphate (ATP) biosensing. ZIF-8, RhB@ZIF-8, MB@ZIF-8, and MeB@ZIF-8 offered CO₂ adsorption capacities of 0.80, 0.84, 0.85, and 0.53 mmol g⁻¹, respectively. The encapsulated cationic molecules improved the adsorption performance compared to anionic molecules inside the crystal. The materials were also tested as a fluorescent probe for ATP biosensing. The simple synthesis procedure offered new materials with tunable surface properties and the potential for multi-functional applications.

Metal–organic frameworks (MOFs) have advanced several technologies. However, it is difficult to market MOFs without processing them into a commercialized structure, causing an unnecessary delay in the material's use. Herein, three-dimensional (3D) printing of cellulose/leaf-like zeolitic imidazolate frameworks (ZIF-L), denoted as CelloZIF-L, is reported via direct ink writing (DIW, robocasting). Formulating CelloZIF-L into 3D objects can dramatically affect the material's properties and, consequently, its adsorption efficiency. The 3D printing process of CelloZIF-L is simple and can be applied via direct printing into a solution of calcium chloride. The synthesis procedure enables the formation of CelloZIF-L with a ZIF content of 84%. 3D printing enables the integration of macroscopic assembly with microscopic properties, i.e., the formation of the hierarchical structure of CelloZIF-L with different shapes, such as cubes and filaments, with 84% loading of ZIF-L. The materials adsorb carbon dioxide (CO₂) and heavy metals. 3D CelloZIF-L exhibited a CO₂ adsorption capacity of 0.64–1.15 mmol g⁻¹ at 1 bar (0 °C). The materials showed Cu²⁺ adsorption capacities of 389.8 ± 14–554.8 ± 15 mg g⁻¹. They displayed selectivities of 86.8%, 6.7%, 2.4%, 0.93%, 0.61%, and 0.19% toward Fe³⁺, Al³⁺, Co²⁺, Cu²⁺, Na⁺, and Ca²⁺, respectively. The simple 3D printing procedure and the high adsorption efficiencies reveal the promising potential of our materials for industrial applications.

Biobased adsorbents and membranes offer advantages related to resource efficiency, safety, and fast kinetics but have challenges related to their reusability and water flux. Nanocellulose/alginate composite hydrogel beads were successfully prepared with a diameter of about 3–4 mm and porosity as high as 99%. The beads were further modified with in situ TEMPO-mediated oxidation to functionalize the hydroxyl groups of cellulose and facilitate the removal of cationic pollutants from aqueous samples at low pressure, driven by electrostatic interactions. The increased number of carboxyl groups in the bead matrix improved the removal efficiency of the adsorbent without compromising the water throughput rate; being as high as 17000 L h⁻¹ m⁻² bar⁻¹. The absorptivity of the beads was evaluated with UV-vis for the removal of the dye Methylene Blue (91% removal) from spiked water and energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) elemental analyses for the removal of Cd²⁺ from industrial mining effluents. The modified beads showed a 3-fold increase in ion adsorption and pose as excellent candidates for the manufacturing of three-dimensional (3-D) column filters for large-volume, high flux water treatment under atmospheric pressure.

A metal–organic framework (MOF) of cerium (Ce) ions and 4,4′,4′′-nitrilotribenzoic acid linker was synthesized via a hydrothermal method. Ce-MOF consists of a Lewis acid moiety, i.e. Ce³⁺ and triphenylamine cores. It showed Fenton-like properties with excellent catalytic oxidation activity for olefins, primary/secondary alcohols, and water pollutants e.g., organic dyes. It displayed high oxidation conversion of cinnamyl alcohol and styrene of 100% and 53%, respectively. It offered good selectivity towards styrene oxide and benzaldehyde (i.e. 75% and 100%, respectively). It was applied for the oxidative degradation of dyes e.g. rhodamine B (RhB), methyl blue (MeB), Congo red (CR), and direct blue (DB) using hydrogen peroxide (H₂O₂) as an oxidant. It exhibited high efficiency in the oxidative degradation of these water pollutants. The mechanistic study of oxidation involves the formation of radical hydroxyl (^•OH) species. This study revealed the possibility of enhancing the oxidative catalytic performance, including oxidative degradation of organic pollutants, by employing advanced oxidation processes (AOPs) using Ce-MOF. The catalyst is recyclable five times without significantly decreasing of the material’s catalytic performance.

The synthesis of magnetic nanoparticles enclosed in zeolitic imidazolate frameworks (MNPs@ZIF-8) was successful carried out at ambient temperature and atmospheric pressure. The synthesis procedure was selected because it is uncomplicated and does not call for the use of any sophisticated pieces of apparatus throughout its execution. The Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) images were investigated to characterize the materials. The analysis of the data allowed MNPs@ZIF-8 to evolve into a highly crystalline phase with particles ranging in size from 50 to 100 nanometers. This was made feasible by the fact that the phase could be created. It was explored whether or not MNPs@ZIF-8 was effective as a nanocarrier for the delivery of natural medicines like crocin. It was demonstrated to be very biocompatible and had an IC₅₀ value of > 1000 μg/mL, which is the concentration at which half of the maximum inhibitory effect is produced. The IC₅₀ value for crocin-loaded MNPs-ZIF-8 was 419 ± 0 μg/mL, which was roughly half of the IC₅₀ value for pure crocin, which was 716 ± 160 μg/mL.

Metal-organic frameworks (MOFs) have advanced several applications, including energy, biomedical and environmental remediation. However, most of the reported MOF materials are in powder form limiting their applications. This study reported the processing of MOF via three-dimensional (3D) printing of cellulose-MOFs (denoted as CelloMOFs). The 3D printing procedure involved a one-pot method including three steps: gel formation, 3D printing, and in-situ growth of MOF crystals. This procedure offered 3D printing of CelloMOF via a binder-free method with high loading of 67.5 wt%. The 3D-printed porous structures were used as adsorbents for carbon dioxide (CO₂), dye, and heavy metal ions. They can be also used as catalysts for the degradation of water pollutants such as organic dyes. The materials can be separated easily without requiring extra procedures such as centrifugation or filtration. The materials offered complete (>99%) removal of organic dyes within 10 min with high selectivity toward anionic dyes e.g, methyl blue (MeB). The materials exhibited CO₂ and heavy metal ions adsorption capacities of 0.63 mmol/g (27.7 mg/g) and 8–328 mg/g, respectively, with good recyclability. Our methodology will open new venues for advanced 3D printing of CelloMOF and its applications for water treatment and air purification.

The development of porous organic polymers, specifically covalent organic frameworks (COFs), has facilitated the advancement of numerous applications. Nevertheless, the limited availability of COFs solely in powder form imposes constraints on their potential applications. Furthermore, it is worth noting that COFs tend to undergo aggregation, leading to a decrease in the number of active sites available within the material. This work presents a comprehensive methodology for the transformation of a COF into three-dimensional (3D) scaffolds using the technique of 3D printing. As part of the 3D printing process, a composite material called CelloCOF was created by combining cellulose nanofibrils (CNF), sodium alginate, and COF materials (i.e., COF-1 and COF-2). The intervention successfully mitigated the agglomeration of the COF nanoparticles, resulting in the creation of abundant active sites that can be effectively utilized for adsorption purposes. The method of 3D printing can be described as a simple and basic procedure that can be adapted to accommodate hierarchical porous materials with distinct micro- and macropore regimes. This technology demonstrates versatility in its use across a range of COF materials. The adsorption capacities of 3D CelloCOF materials were evaluated for three different adsorbates: carbon dioxide (CO₂), heavy metal ions, and perfluorooctanesulfonic acid (PFOS). The results showed that the materials exhibited adsorption capabilities of 19.9, 7.4–34, and 118.5–410.8 mg/g for CO₂, PFOS, and heavy metals, respectively. The adsorption properties of the material were found to be outstanding, exhibiting a high degree of recyclability and exceptional selectivity. Based on our research findings, it is conceivable that the utilization of custom-designed composites based on COFs could present new opportunities in the realm of water and air purification.

Metal–organic frameworks (MOFs) improved several trends and are promising for industrial applications. However, current synthesis processes offer powder form, rendering their applications difficult. A simple solvothermal method offered an in situ growth of copper-based MOFs, for example, CuBDC (BDC: benzene-1,4-dicarboxylic acid) into a cotton textile; the material was denoted as CuBDC@Textile. CuBDCTextile was used as a solid sensor and adsorbent for volatile organic compounds (VOCs). It exhibited good vapochromic properties that enabled a colorimetric detection of pyridine (Py) via naked eyes with high selectivity and good sensitivity. Adsorption of pyridine via pervaporation using CuBDC@Textile was recorded. CuBDCTextile is a flexible textile with a high adsorption capacity (137.9 mg g⁻¹) toward pyridine. It offered dual functional: sensor probe and adsorbent. The synthesis of CuBDC@Textile and their excellent performance as a sensor and adsorbent are promising for further investigation of the “MOFs on textile materials” topic.